_ In this weeks’ Blog I am going to show you how easy it is to understand UL ratings on Cable.  This is often an area of confusion as we have the BS Standard CSA (Canadian Standards Association) & UL (Underwriters Laboratories) Ratings it’s hard to know where to start of which standard to adopt.

For many the default standard of choice is the UL for cable & wire.  The main reason for this is the international association of the standard.  Pretty much everywhere in the world recognisees the standard.  What’s more the leading brands such as Belden & Alpha use UL ratings as standard.

Assuming we are also going to adopt UL as the standard of choice what do we need to know.  Here is a quick guide to UL marking on cable direct from the UL website:

What is the relationship between the UL Standards for wire and cable and the National Electrical Code?

The large majority of UL's wire and cable Standards are intended to be compatible with the installation requirements of the National Electrical Code (NEC). Some exceptions are boat cable, marine shipboard cable, and appliance wiring material. UL staff devotes significant resources to the development of the NEC, which is published by the National Fire Protection Association (NFPA).  

Does an E-number on a product mean that it is UL Listed?

No. The UL E-number is a valid identifier for the organization responsible for a product but not an indication that the product is Listed, Classified, verified or Recognized. Only the appropriate UL Mark -- on the wire or cable or on its packaging -- is a valid indication of UL certification. UL assigns a unique E-number (E and a 3- to 6-digit number for wire and cable products) to each applicant in every product category. To find the responsible organization for a product when the E-number has been used for identification, go to UL's Online Certifications Directory, select "Search By UL File Number" and enter the E-number.

Why are ampacity markings not permitted on UL Listed wire and cable, and not shown in UL wire and cable Standards?

The ampacity of a wire or cable is the amount of current that the wire or cable can transmit without exceeding its rated temperature. An ampacity marking on a wire or cable or a reference to a specific ampacity for a wire or cable in a UL wire or cable standard is not feasible since ampacity varies according to the actual conditions under which the cable will operate. These conditions include the ambient temperature, installation environment (e.g., free-air), conduit or directly buried in the earth. The National Electrical Code provides two methods for the cable user to determine ampacity for a cable based on the installation conditions.

What does the term "verified" mean?

The term "verified," when used in a UL marking, means that the product has been tested and complies with one or more specific requirement. These requirements may be safety- or performance-related. In the UL system, the words "Classified" and "verified" mean the same thing. For a complete explanation of "Listed," "Classified" and "Recognized," read more on the UL Mark.

What is the best source of information on the intended use of a UL Listed wire or cable product?

The guide information for most of UL's product categories provides valuable information regarding intended use and installation requirements. To view this information, go to UL's Online Certifications Directory. Use the keyword search to determine the links to files that are appropriate. Each file contains an additional link to the guide information.

Do the style numbers for Appliance Wiring Material (e.g., 1015) have any significance?

The significance of the numbering systems is as follows:

Style range     Description

1000-1999     Single conductor, thermoplastic-insulated wire

2000-2999     Multi-conductor, thermoplastic-insulated and jacketed wire

3000-3999     Single conductor, thermosetting-insulated wire

4000-4999     Multi-conductor, thermosetting-insulated and jacketed wire

5000-5999 Single and multiple conductor specialty item    s

10000-19999 Continuation of Section 1

20000-29999 Continuation of Section 2

For additional information, refer to the guide information for category AVLV2 -- Appliance Wiring Material.

The Appliance Wiring Material style pages include text such as "Marking -- see page 13." What document does this reference?

The UL appliance wiring material style pages are currently being revised. References within the style pages are obsolete. Instead, refer to the guide information for AVLV2 -- Appliance Wiring Material.

I hope this has helped yopu and look out for my future blogs on this subject designed to help you improve your knowledge and build better products!

_For my fist blog of the year I thought I'd start with a new product innovation from 3M.  For those of you who are into high-speed data then this is for you!

The 3M Internal Twin Axial Ribbon Cable SL8800 Series is a new ultra low-profile, high-speed, high signal density cable. The products in the SL8800 Series are only the first of a new family of high-performance cables from 3M.

The information in the 3M tech specs state the SL8800 Cable Series is a longitudinally shielded cable construction and is made to exacting tolerances. The cable suffers little to no resonance or "suck out," where traditionally spiral wrapped twin axial cables exhibit an enormous loss of signal at a particular range of frequency.

The cable is also low skew, and the ribbon construction allows customers to further control any skew that can sometimes be introduced when trying to manage individual channels. This is especially critical at speeds beyond 10 Gbps. High speed applications continue to demand more performance out of the cables, and the SL8800 Series Cable will deliver that performance for years to come.

_As signal speeds continue to increase, cable can improve but the termination can still be a weak point. The SL8800 Series Cable standard ribbon format supports high performance termination, repeatability, and a reduced possibility for pinout error. When stripped in parallel, and then applied in parallel, each channel results in an identical termination length. Control and placement of individual channels is not required, eliminating the variation in performance and rework due to incorrect placement.

Ok, now my take on this is that this cable really is quite special, apart from the obvious space saving this cable really does seem to be very special and offers design engineers the opportunity to save more space and increase their data throughput.  

My only criticism is the cable is virtually impossible to strip and prepare for termination. The tooling is massively expensive so until the costs come down it will be difficult for many smaller OEMs to adopt.  Still that is always the way with any new technology.

For more information and very interesting technical information check out the promotion video.